Robotic science rovers operating on the lunar surface over diurnal cycles face extreme temperature environments (-200 to 120 °C) beyond conventional energy storage batteries operating limits, even with shielded and articulated radiator assemblies. These hot and cold lunar conditions can last several Earth days, because of the slow rotation of the Moon, or permanently in shadowed craters and poses the significant challenges to small, low-power (~100 W or less) payloads, rovers, and landers required for lunar science, and survivability of the rovers electrical power subsystems during lunar day/night becomes a critical issue. As such, one strong technology candidate for meeting future lunar electrical storage thermal management needs are ThermoElectric Coolers (TECs) which are a well-established technology (> $1.1B market in 2021). TECs are solid-state, lightweight, have no moving parts or working fluids, and operate with highly reliable, uninterrupted, low maintenance, and environmentally-friendly cooling. Toward this goal, Nanohmics team proposes to develop a TEC system suitable for lunar electric power subsystems cooling during lunar day, and high-efficiency heating during the lunar night. The proposed Thermoelectric Temperature Regulation Unit (ThermoTruTM) will employ modular printed circuit boards (PCBs) based TEC devices that can be configured to meet thermal power dissipation shortcomings to address the lunar day cooling needs (radiator T = 30 – 35 °C, ∆T > 15 °C, 10 – 100 W of heat lift) and lunar night heating needs (electronics at > -20°C, ∆T to radiator > 20 °C, and radiator T ~ -50 °C) for small rover EPS survivability. A lunar night heating subsystem for small rovers currently does not exist. Using the combined benefits of compact cooling (day) and efficient heating (night) in a single, all-passive (i.e. no mechanical thermal switch) has numerous benefits for lunar rover and other lunar surface systems.
The proposed work will develop high efficiency thermoelectric convertor (TEC) systems which will increase the survivability of lunar rovers’ battery storage during day/nighttime by cooling/heating operations and extend the NASA mission times. These modular and conformal TECs can be used in many NASA missions, which require localized cooling/heating needs. Furthermore, the highly efficient TEC designs will also enable to use thermoelectric technology for many other space cooling and power generation missions.
Efficient TECs provide a means to meet next generation smart cooling needs which can reduce the CO2 and greenhouse gases emission compared to competitive cooling systems. These mass-marketable TECs can replace most multistage TECs and compression-based systems in other applications such as automotive, defense, biomedical, and waste heat recovery markets which are worth more than a billion dollars.